Method of setting coloring and coating compositions



May 9, 1939- c. J. M A RTHUR 2,157,38T

METHOD OF SETTING COLORING AND COATING COMPOSITIONS ,F'iled Jan. 22, 1937 INVENTOR ATTORNEY Patented May 9, 1939 PATENT OFFICE .METHOD OF SETTING COLORING AND COATING COMPOSITIONS Charles J. MacArthur, Glen Ridge, N. 1., assign or to Interchemical Corporation, a corporation of Ohio Application January 22, 1937, Serial No. 121,832

Claims.

This invention relates to an improved method of setting a printing ink and the like, and to improvements for this purpose.

A process of printinghas been developed in which, instead of the usual ink composed of a pigment dispersed in a there is employed a printing paste comprising a pigment, colloidal material for binding the pigment'to the printed sheet, and a solvent for the 10 binding'mat'erial, and als -in some cases, for the I coloring matter, which-is substantially non-volatile at room temperature. Two principal methods ofstting the ink ijl m to a solid condition have been devised. One of these involves applying heat to the ink to convert the solvent to a vapor, and the other involves applying to the inked surface of the printed sheet a diluent, such as water, which "is miscible 'with the solvent and which is a nonsolvent for the colloidal binding material and 0 coloring matter, to reduce the solvent concentration and thus precipitate the binder. and coloring matter. The first of these methods involves the use of special heating equipment, and a high' degree of heat. With certain types of stock and specific printing conditions, such extremelyhigh temperatures are not desirable. In the second of these methods, it has proved diflicult to apply the proper amount of diluent (usually water) without danger of weakening or otherwise. damaging the printed material. Furthermore, there is a tendency for some of the solvent to remain on theprinted sheet in the vicinity of the ink solids,with

the result that, upon evaporation of the relatively volatile diluent, the relatively non-volatile solvent may redissolve the binding material and thus resoften the ink.

' According to the preferred practice of my invention, I support the prlntedrweb on a heated surface, and during the heating and while it is sup- 40 ported, contact the printed face of the web with a precipitating fluid. For the applicator of my precipitating fluid, I prefer to employ a web of adsorbent material, which is wet with the precipitating fluid, and which, in its travel, withdraws a portion of the mixture of solvent and diluent, from the ink on the printed web. The printed web preferably passes into contact with the surface of ahot roll just prior to contact with the moistened web, so that the rear face of the printed web is supported on and heated by the hot roll at the instant that, and during the period that, the inked face of the printed web contacts the moistening web. .The time of contact between the printed web and the moistened web or other applislow-drying, oil varnish, 7,

cator is advantageouslymomentary, and thereafter the printed web preferably continues in contact with the hot roll for a period of time sufficient to evaporate any excess liquid from the printed material.

Thus, the adsorbent moistening web has the effect of substantially instantaneously precipitating the binding material and coloring matter and solidifying the ink, and it also carries some of the solvent from the presence of the printed web and 1 the ink solids; and the application of heat to the printed web assists the penetration, into this web,

'of whatever diluted solvent is not taken up by the adsorbent web. Any small amount of excess liquid remaining on the printed material, after the 15 completion of the adsorbing and moistening operations, can be readily evaporated. The setting of the ink to a non-smudging and permanently dry condition is efficiently accomplished, without the need for high-temperature burners, without dan- 20 ger of soaking the printed sheet, and without the employment of cumbersome and highly expensive apparatus.

A specific feature of the invention lies in a means for preventing the concentration of solvent 25 in the moistening web from rising above a predetermined maximum. A more detailed feature lies in pressing the moistening web against the printed sheet with progressively increasing pressure from the point of original contact to the point 30 of last contact, which appears to aid in adsorbing the solvent and in distributing a portion of the precipitating fluid and the solvent into the surrounding portions of the sheet, away from the ink solids, particularly when the printed sheet con- 5 sists of porous material such as ordinary paper.

Other features, objects and advantages of the present invention will in part be pointed out' and in part become apparent in connection with the foliowing'detailed description of one illustrative 40 form of the invention, reference being had to the accompanying drawing, wherein the figure is-.a diagrammatic side elevation of apparatus adapted for present purposes.

Referring to the drawing, a web 5, of paper or' the like, as it comes from a rotary printing press including plate cylinder l0 and impression cylinder I I, passes between a moistened web I, driven through pulley 9, and a hot roll or drum 8, also positively driven. The webs 5 and 1 preferably move at the same speed, and meet at an angle just after the printed web 5 contacts the hot roll, so that the printed face of web 5 is moistened while its rear face is supported on a hot surface. 5

In order to provide the proper contact between the moistened web and printed web, mechanism of the following character is advantageous: An idler pulley I2 is adjustably mounted through a jack I3 on frame H, the pulley I! being positioned so that it holds a portion of the web 1 against the printed face of the web 5, over a small portion of the circumference of the hot roll or drum 8. The frame It ispreferably pivoted, as at l5, upon a suitable rigid support I1, and the free end of the frame may be adjustably mounted through a jack it upon another rigid support l9. Intliis manner, the frame I 4 may be moved about its pivot, and the position of pulley I2 may be adjusted relative to the frame, in order to vary the length of contact and the different pressure desired between the webs 5 and 1. For adjusting the tension of the web 1, an additional idler pulley 20 may be mounted through a worm-and-wheel device, indicated diagrammatically at 2|, so that, upon turning the hand wheel 22, the position of the pulley 20 may be varied to take up slack.

The web 1 passes beneath a suitable spray device 23 which is adapted to distribute water or other precipitating fluid onto the surface of the web prior to its contact with the inked face of the printed web. For reducing the amount of liquid in the moistening web after it contacts the printed web, and thus removing solvent which the web has adsorbed from the printed material, the web is passed through a wringer including squeeze rolls Z4 and 26, mounted above a trough 25. For varying the pressure between the rollers, the roller 26 may be mounted on a pivoted arm 21 engaged by a threaded member 28 on a pivoted rod 29. By screwing the member 28 downward, the arm 21 is depressed, and the force exerted on the web I is thus increased to control the amount of liquid removed from the web.

The hot roll or drum 8 may be mounted on a shaft 30, positively driven in synchronism with the printing press, and may be heated in any convenient manner, for instance; by circulating steam through its interior or by a gas flame directed against the inside surface of the drum from a jet located within the drum just prior to the point on its circumference at which it meets the moistening web. Preferably, the drum and guide rollers may be arranged so that the web contacts the major portion of the circumference of the drum; in order to avoid the use of an excessively large drum. From the drum 8, the

printed web passes over guide rollers 3| and 32,

and thence to rewind rollfl. A cooling rollerrnoving at a different speed than roller 3| may be positioned in contact with roller 3| to provide a calendering action while the web is still' warm. If desired, it may be treated to a jet of cold air supplied by a blower 33, at a convenient point prior to rewinding.. I

It will be appreciated that many different solvents and binders may be employed; for instance, diethylene glycol monobutyl ether acetate as a solvent and nitrocellulose or a suitable resin as the binder. The following examples illustrate Example II Parts by weight Carbon bla 14 Prussian blue 6 Ester gum 47 5 Diethylene glycol monobutyl ether 31 Syncorn wax 2 In case the solvent is not miscible with water, other similar precipitating fluids can be employed, such as carbon tetrachloride.

In the operation of apparatus according to the invention, the temperature of the drum may vary depending upon the solvent used and the material printed upon. In most cases, a temperature of about 225 F. is suflicient. Since most of the solvent has been" removed from the presence of the printed web and the ink solids by the adsorbing and moistening operation, and the coincident heating, very little solvent remains in the vicinity of the ink solids after the completion of the moistening operation, and whatever small amount of liquid remains on the sheet is mostly diluent. This minute amount of liquid can be evaporated, if necessary, by continuing the heating, after the completion of the moistening operation, at a temperature much below that required to evaporate all or a major portion of the solvent from the ink.

Through the present invention, there is thus 'provided a simple, convenient and rapid method of treating an ink containing a solvent which is substantially non-volatile at room temperature, in order to set the ink to a non-smudging condition, so that the ink does not smear or offset, when the web is rewound, or printed on the other side. By supporting the printed material during themoistening operation, the amount of diluent applied can be accurately controlled, and danger of weakening the material is avoided, as is par- 40 ticularly important in the case of a continuously traveling web of paper or the like, which, otherwise, would be apt to be stretched and crinkled or torn. The subjection of the web to a calendering action after the moistening operation, has the advantage of smoothing the paper and improving the gloss of the ink and paper.

It will be appreciated that the manner of applying the diluent may be varied, and that the heating means is not restricted to a hot roll. Moreover, the invention, in its broadest aspects, is not restricted to the use of a web, as it may be employed for treating separate sheets. i

The terms and expressions which have been employed are usedas terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of exeluding any equivalents of the features shown and atype of ink which can be printed and set ac- V cording to the present invention:

Example I V Partsby weight Permanent Peacock blue 30 RS nitrocellulose V second viscosity (wet "with 30% alcohol) 30 II Diethylene glyoolmonobutyl ether acetate.

described, or portions thereof, but itis recognized that various modifications are possible within the scope of the invention claimed. For instance, coating compositions containing a solvent and a binder or coloring matter soluble in the solvent, may be employed to color the material subjected to the setting treatment described herein.

What I claim is:

1. A method of setting a printing ink and the like, including a solid component and a solvent therefor, which comprises diluting the ink on the printed material with a fluid which'is miscible with said solvent and which is a non solvent for said 'solid component, supporting the printed material substantially throughout its entire treated area during the diluting operation and removing substantially all the diluting fluid while the printed material is so supported.

2. A method of setting a printing ink and the like, including a solid component and a solvent therefor, which comprises diluting the ink on the printed material with a fluid which is miscible with said solvent and which is a non-solvent for said solid component, supporting the printed material substantially throughout its entire treated area during the diluting operation and evaporating substantially all the diluting fluid while the printed material is so supported.

3. A method of setting a printing ink and the like, including a solid component and a solvent therefor, which comprises diluting the ink on the printed material with a fluid which is miscible with said solvent and which is a non-solvent for said solid component, supporting-the printed material substantially throughout its entire treated area during the diluting operation and applying heat to remove substantially all the diluting fluid while the printed material is so supported.

4. A method oi setting a printing ink and the like, including a solid component'and'a solvent therefor, which comprises diluting the ink on the printed material witha'fluid which is miscible with said solvents and which is a non-solvent for said solid component, supporting the printed material substantially throughout its entire treated area on a hot supporting surface during the diluting operation and substantially evaporating all the diluting fluid while the printed material is so supported.

5. The method of setting a printing ink including a pigment, a binder and a solvent therefor which is substantially less volatile than water, which comprises diluting the ink on the printed material with a fluid as volatile as water which is miscible with said solvent and which is a nonsolvent for the binder, immediately removing a portion of the mixture of diluting fluid and solvent from the presence of the ink solids, and heating the printed material during the diluting operation to cause the remainder of the mixture to penetrate .into the printed material to leave the solvent which it contains out of contact with the binder when'the volatile fluid evaporates.

$.The method of setting 'a printing ink ineluding a pigment, a binder and a solvent therefor which is substantialy less volatile than water, which comprises diluting the ink ongthe printed material with a fluid as volatile as water which is miscible with said solvent and which is a non-' solvent for the binder. immediately removing a g portion of the mixture of diluting fluid and solvent from the presence of the ink solids, and heating the printed material during the diluting operation to cause the remainder of the mixture to penetrate into the printed material, and continuing the heating thereafter to evaporate the volatile fluid leaving the solvent in the printed material out of contact with thebinder.

7. The method of setting an ink including a pigment, a binder and a solvent therefor, which comprises momentarily contacting the printed ink with adsorbent material containing a diluent which is miscible with said solvent and which is a non-solvent for said binder, withdrawing said adsorbent material from the printed ink, and heating the printed material.

8. The method of setting an inkv including a pigment, a binder and a solvent therefor which is substantially non-volatile under the conditions of the printing operation, which comprises momentarily moistening the printed ink with a relatively volatile liquid which is miscible with said solvent and which is a non-solvent for said binder, distributing-the mixture of solvent and volatile liquid through the printed material and thereafter heating the printed material to a temperature *not greatly above the boiling point of said liquid to evaporate the volatile liquid and leave the solvent in the printed material out of contact with the binder.

9. The method of printing, which comprises applying to the material to be printed an ink including a pigment, a binder and a solvent therefor which is substantially non-volatile under conten ed with a relatively volatile liquid which is a non-solvent for said binder and which is miscible with said solvent,- withdrawing said adsorbent material, and heating the printed material both during and after the moistening operation.

10. The method of printing which comprises printing upon a continuously traveling web with an ink including a pigment, a binder and a solvent therefor, supporting the printed material upon the surface of a rotating drum, applying to the inked face of the printed material, while ,supported on said drum, a liquid which is a nonsolvent for said binder and which is miscible with said solvent, and heating the printed material while it is supported on said drum and following the moistening operation.

- CHARLES J. MscAR'I'HUR. 

